194 MOSQUITOES. 
these frail flies can inflict; at times they drive everyone from 
the boat, and trains can sometimes only run with comfort 
on the Northern Pacific by keeping a smudge in the baggage 
car and the doors of all the coaches open to the fumes.”’ 
Prof. Riley wrote the above lines many years ago, and 
conditions have greatly changed since. The mosquito is 
stilla great pest in some places in Minnesota, sometimes 
even killing animals that can not escape it, but the 
prairies are rapidly settled in spite of them, and as the land 
is gradually better drained mosquitoes become fewer and 
fewer. They are very abundant north. In Davis’s straits, 
in lat. 72° N., Dr. Bessels, on board the Polaris, was obliged 
to interrupt his observations on account of the multitudes 
of these insects. A great number were also seen up to the 
Sist. deg. of latitude. An old writer, writing about the 
northern shores of Lake Superior, expresses himself in this 
way: ‘When the mosquitoes disappeared the black-flies 
came; the mosquito pumps up a drop of blood and flies 
away, the black-fly bites and makes a wound which con- 
tinues to bleed.”’ 
In tropical America these insects are still worse, and 
they are the source of such incessant torments that some of 
the most beautiful regions of the globe are unfit for a white 
population. In the llanos and prairies of Venezuela they 
persecute cattle to such an extent that they do not thrive 
even on the richest pastures. 
Of the many species found in our state a few have been 
studied more in detail, as well as their life-history. The illus- 
trations (figs. 154, 155, 156 and 157) show a common 
species ( Culex pungens Wied.); it is the first seen in the spring 
and the last to disappear late in autumn. Fig. 154 shows 
the male, and some of the peculiar scales found upon the 
veins of the wings; the first three joints of one of the feelers 
is greatly enlarged, to show the auditory organ (Johnson’s 
organ). Fig. 155 shows the female, fig. 156 the full-grown 
larva, a bunch of hairs from the tail, an egg mass and the 
enlarged egg; fig. 157 shows the pupa. The color of both 
male and female is dark gray with lighter yellowish-white 
bands. 
